One type of fluid ejection device is a thermal inkjet printing device. A thermal inkjet printing device forms images on media like paper by thermally ejecting drops of fluid onto the media in correspondence with the images to be formed on the media. The drops of fluid are thermally ejected from the thermal inkjet printing device using a heating resistor. When electrical power is applied to the heating resistor, the resistance of the heating resistor causes the resistor to increase in temperature. This increase in temperature causes a bubble to be formed. The bubble, in turn, pushes fluid through a small orifice, thereby ejecting a fluid drop.